This invention improves the efficiency and functionality of a grid-tied power system that utilizes one or more local power sources and one or more local energy storage devices. The purpose of the invention is the coordination, optimization and efficient control, regulation, and transfer of electrical energy among several energy storage devices, power generators, the utility grid, and connected local electrical loads. The coordinated control and utilization of local storage and generation combined with coordinated integration with the utility grid results in an overall system that can be more flexible, economical, and efficient than any of the individual components can be, when operated separately.
In poly-phase power distribution systems, it is desirable to balance the loads on the individual phases of the system. Ideally, the loads on all the phases should be close to equal or balanced. For example, it would be unacceptable for the loads on one phase to greatly exceed the loads on the other phases of a poly-phase system. As used herein, the word “balanced” means that the loads on the individual phases are equal within acceptable limits for the power distribution system in use; however, it does not mean that the loads on each phase are exactly equal or that the loads on all phases are non-zero.
Traditionally, load-balancing is accomplished by the electrician wiring the system. To do this, the electrician must keep an accounting of the power requirements of all the loads on each phase and add loads to, or remove loads from, each phase as necessary to achieve the desired balance. This method is very tedious and time consuming, during the installation of the system. In addition, for larger number of loads, this is not practical for a person to account for, and becomes very inefficient, inaccurate, and slow.
U.S. Pat. No. 5,934,096 discloses a wiring system for commercial refrigeration which permits power to be balanced among three phases of electrical power, which is an example of a traditional way of load-balancing, in addition to a good explanation of other prior art.
Some of the prior art are listed here:                U.S. Pat. No. 7,239,044: Enhanced distributed energy resource system (Sandia Corp.)        US Patent application: 20060250902: Plug-in hybrid vehicle with fast energy storage (AFS Trinity Power Corporation)        US Patent Appl.: 20050006958: Grid-connected power systems having back-up power sources and methods of providing back-up power in grid-connected power systems (Morningstar)        U.S. Pat. No. 6,297,980: Unified constant-frequency integration control of three-phase power corrected rectifiers, active power filters, and grid-connected inverters (Univ. of California)        U.S. Pat. No. 7,207,405, Hybrid power supply apparatus for battery replacement applications, which addresses mobile applications.        U.S. Pat. No. 6,671,585, System, method and computer program product for enhancing commercial value of electrical power produced from a renewable energy power production facility, which is of a high concern now, due to importance of energy and high cost, plus the environmental concerns.        U.S. Pat. No. 4,849,648, A system and method of selectively deployed and utilized compressed air energy storage satellite facilities within an electrical power grid network, for the alternative methods used in industry.        U.S. Pat. No. 5,845,479, Method for providing emergency reserve power using storage techniques for electrical systems applications, for backup/emergency systems.        
However, none of the prior art (above) teaches the features of the current invention, mentioned below.